Vacuum electric discharge device



Apr. 3, 1923.

H. w. EDMUNDS-ON ET AL. v

VACUUM'ELECTRIC DISCHARGE DEVICE.

FILED MAR. 10, 919-v L MGAB.

Inventors Herbert W. Edrn undson,

\X/i Ham Tmur'xro, by 1 .f' A?! 7 Att orn ey.

Their Patented Apr. 3, 1923.

NHTE sr T E S HERBERT W. EDMUNDSON AND WILLIAM '1. MUNRO, OF RUGBY,ENGLAND, ASSIGNORS TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEWYORK.

VACUUM ELECTRIC DISCHARGE DEVICE.

Application filed March 10, 1919. Serial No. 281,649.

To all whom it may concern:

Be it known that we, HERBERT WATSON EDMUNDSON and WILLIAM TOM MUNRO,subjects of the King of Great Britain, residmg at Rugby, in the countyof Warwickshire, England, have invented certain new' and useful Imrovements in Vacuum Electric Discharge .evices, of which the follow-;in%is a specification.

nated as far as possible.

According to our invention a shield preferably of metal is mountedwithin the device in such a position as to cut off the heat radiatedfrom the anode durin operation of "the device. This shield may e ofdifierent shape according to the construction of the discharge device,and is separated from the anode so that the vacuous space between it andthe latter serves to prevent it from becoming heated to any considerableextent.

In applying the invention to a form of valve in which the cathode islocated within .{a cylindrical anode, the whole being mounted on a glassstem within an evacuated bulb,

the stem carrying the leading-in conductors for the device, the shieldmay be in the form of a cylinder of thin sheet metal almost completely,or completely, surrounding the anode or interposed between the anode andstem in any convenient way so as to prevent the stem through which theleading-in wires pass from being heated by direct radiation from thesurface of the anode. As a result the heat radiated from the anode willbe prevented from injuriously affecting the seal.

If allowed to act on the seal the heat radiated from the anode mightcause electrol-- ysis with the evolution of gas from the glass itself.This heat might also cause cracks to form along the leading-inconductors thus allowing the surrounding gases to leak into the interiorof the device and impair the vacuum. In devices of the general class towhich our invention, relates, the allowable voltages which may beapplied between the various leading-in conductors depends largely uponthe temperature of the glass between the conductors. It is therefore ofimportance, where high voltages are to be used, thatthe seals should bemaintained at as low a tem perature as possible.

The accompanying drawings illustrate one form of our invention, Fig. 1being an end elevation and Fig. 2 a side elevation partly broken away.

In the drawing, 1 represents an evacuated receptacle provided with theglass stem 2 into which the supporting wires and the conductors throughwhich current is supplied to the various parts are sealed. 3 is afilament adapted to operate as a hot cathode,

and'4 is the anode which receives the bom-v bardment of electrons givenoff by the cathode. Surrounding this anode we provide a shield 5 whichis held in place by a support 6 sealed into the stem 2. In themodification illustrated the shield is formed by doubling a sheet ofthin metal and bending it into the form of a cylinder, the two portionsof the plate bein spaced apart so that they form substantiafiy twoconcentric cylinders concentric with the anode 4, which in this case isshown as a cylinder. The shield 5 may be secured to the supporting wire6 many convenient manner, for example, a tongue 7 may be stamped fromthe sheet in proximity to the bend and bent upwards. This tongue may besoldered or welded to the end of the supporting wire in any well knownsuitable manner.

The shield also prevents conductive material due to the disinte rationof the anode or cathode from being leposited on the stem and seals whereit is usually largely depositedv and where it may act as a conductivebridge between the leading-in wires and impairs the efliciency of thedevice.

While we have illustrated and described only one form of our invention,it will be apparent to those skilled in the art that many variations maybe made in the form of the shield as well as in the manner in which itis placed and supported in the device with out departing from the scopeof our invention as setforth in the appended claims.

What we claim as new and desire tose-.

cure by Letters Patent of the United States, is

1. The combination in an apparatus of the class described of anevacuated receptacle containin a cathode adapted to be heated to incanescence and an anode adapted to receive electrons from said cathode,leadingin conductors sealed into the walls of said.

receptacle for supplying current to said cathode and anode, and ashieldinterposed between said anode and the region where said leading-inconductors are sealed into the walls of the receptacle for interceptingreceptacle.

heat radiated from the anode said shield being out of contact with thewalls of the 2. The combination in an apparatus of the class describedofan evacuated recepand anode, and a shield interposed between saidcathode and anode and, the region where said leading-in conductors aresealed into tacle.

the walls of the receptacle for preventing the overheating of thatregion otthe walls which surrounds the leading-in conductors said shieldbeing out of contact with the.

adapted to be bombarded by electrons from said cathode, leading-inconductors for supplying current to said cathode and anode, a stem forsaid receptacle through which said leading-in conductors are sealed, anda shield interposed between said cathode and anode and said stem forpreventing the overheating of the stem said shield being out of contactwith the In Witness whereof, we have hereunto respectively set our handsthe 12th day of February, 1919, and the 8th day of March,

i H. W. EDMUNDSON.

I WILLIAM T. MUNRO. Witness to the signature of the said Herbert WatsonEdmundson:

JOHN HALFORD, DOROTHY WHITE.

walls of the recep-

